The invention relates to an oil fryer cooking system, and more particularly to a filtration system for an oil fryer which filters the oil in a more convenient and effective manner.
With the advent of fast food restaurants, the art of fast food fryers has seen much development. In order to increase the life of the cooking oil in deep fryer systems, filtration of the oil in a safe and efficient manner is needed. Typically, a fast food restaurant will filter the oil in each vat of the fryer about once a day. The typical deep fryer system in a restaurant will include a plurality of fryer vats. The prior art filter systems typically have included a reservoir in which the oil is drained from a vat. The drain reservoir normally includes a screen or paper filter at the bottom of the reservoir through which the oil is withdrawn from the reservoir and returned to the vat. Typically such a paper filter is good for filtering about 3 vats. In the case of paper or fabric filters, it is difficult to seal the filter around the edges of the reservoir so that some unfiltered oil is able to pass around the edges. Rather than being forced through the filter at a high pressure, the oil is usually drawn through the filter by suction. Prior art deep fryer systems for filters are shown in U.S. Pat. Nos. 4,974,501, 4,444,095, and 4,328,097.
It is also known to use filtered cooking oil for rinsing out the vat, such as disclosed in U.S. Pat. No. 3,707,907 wherein a valve is utilized to close off the return line to the oil vat forcing the filtered cooking oil through a quick release connector to which a rinsing nozzle is connected. The filtered oil passes through the nozzle for rinsing. This assures that all the particles are rinsed from the vat before the vat is refilled with filtered cooking oil. U.S. Pat. No. 4,959,144 discloses the use of a filter to remove larger particles and then a second low pressure filter for removing finer particles. However, the embodiment results in a relatively expensive and complicated construction. Again the filtration provided by the low pressure filter is somewhat limited due to the use of conventional screen and filter pads. There is considerable plumbing in the apparatus which allows for the oil to solidify.
Accordingly, an object of the invention is to provide a filtration unit for a deep oil fryer which provides increased filtration for longer oil life in a simple and reliable manner.
Another object of the invention is to provide a filtration unit for a deep oil fryer which incorporates a pressure filter which is highly effective for filtering the cooking oil and a pre-filter which is utilized to filter the large particles prior to the pressure filter.
Another object of the invention is to provide a deep oil fryer and filtration system having a compact filtration unit, having a by-pass system which allows pre-filtered cooking oil to be used for rinsing the vat but without passing the rinsing oil through the final pressure filter.
Another object of the invention is to provide a highly effective and efficient filtration unit for filtering cooking oil from deep fryers wherein a pressure filter is utilized having a highly efficient filter element which is long lasting, yet easily replaceable when a replacement is needed.